2 into 1 intake jetting issues

Schmeck750

If you can't buy it, build it.
Hey all, new to this site and hopefully can find someone to help me out . I have a 79 kz750 twin with a 2 into 1 intake that I made for it . I am running a keihin pwk 36 from a 99 suzuki Rm125 2 stroke. It runs pretty rich considering the jets are stock . 180 main and 55 pilot ( may be wrong) . It idles like crap and spits at me lol . High rpms it is fine but Im trying to figure out what pilot jet size I will need without buying a bunch . I have black soot on my plugs and exhaust so far. I was thinking 35 (smallest pilot jet offered) but I do not want to run too lean and lock my motor up . Any help here would be awesome , Thanks -Tyler
 
If someone could also explain jet sizes to me also. I read that running rich you need to go up in size .I figured you needed something smaller just because it makes sense to go down in size for less fuel.
 
First up... a 36mm carb is going to be on the small side for a 750 twin.

Second... ignore plug color unless you're doing a proper chop. Carbs spitting indicates a lean condition.

Third... By high RPMs you mean revving it in the driveway or actually taking it out on the road?

Finally... higher number jets means more fuel.
 
way to lean and you may not get that carb rich enough to work

its to small

and they only make up to a 230 main probably still to lean for your app

you will need at least a 50 slow jet
 
wow, I figured this carburetor was running too rich but in fact it was probably running too lean . I am basically running 3 copper elbows and a tee . Its not A long intake so as far as velocity(sp) goes its probably not getting much . I have a set of bs38 carbs but its difficult to find jets for unless your buying a rebuild. Id like to stick with this pwk36 but if I had to get a bigger carburetor what would be a decent carburetor? oh and high rpm is yes in my driveway . I did not want to drive it until I got the idle/slow jet worked out . Then I would move on to the next jet. Also, if anyone makes a 2 into 1 intake for under 150$ please refer me . Sold my tig welder a year ago and wish I hadnt lol.
 
where are you located?\

can you post some pics?

i have a few 750s running on a single vm38 mm mikuni and they work decent
 
It wont let me load the images from my phone . is there another way to do this other than attachments.
 

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put it back to stock, feel the pleasure of riding.................
or .......continue to hit yourself in the face with a 2x4 ,WHAT
 
personally I cant stand the stock bs38 carbs. Running a single carb would be a better option to me . But ofcourse , everyone has there own opinion .
 
I could probably use one bs38 out of the two but I definently need a better 2 into 1 intake .
 
bs 38 is a constant velocity diaphragm carb good luck with that as a single and finding jets for it

that would be a custom designed nightmare IMO

never mind the intake lol
 
You are probably right. I have been looking around and I do like the intakes from joewiseguy customs. I do not know if they make one for a kz750 twin though. I emailed them a while back and never got a reply. Maybe I should call instead and ask about them.
 
Schmeck750 said:
I could probably use one bs38 out of the two but I definently need a better 2 into 1 intake .
what kind of experience do you have tuning motorcycles?
and what kind of mufflers are those ?
 
Talked to joe from joewiseguy customs and there shouldn't be a problem with the 36mm carb I am running . Just need richer jets. I'm gonna do this right, go to arcet and rent myself a gas bottle. Mig up a nice intake system . Anyone ever use the rubber boots and just take the rubber off for a metal manifold?
 
The mufflers are exhaust tips from an auto parts store. I welded it from the inside to keep the chrome from getting messed up . I have Harley baffles that I can insert for back pressure . Currently has no baffles because I like the sound (and it lets people know where I am ).
 
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